Variable P Angle for Plane Envelope Hourglass Worm

This paper developed a new type hour-glass worm enveloping by a variable P angle of the generating plane, and obtainned all of the equations of the worm. The drive by this worm will improve its profile in appearance sharp-pointed or undercut under the small velocity ratio.This paper was theorized about with the "Methodology of Envelope" devised by Beijing University of Iron and Steel Technology,